搭接量对激光淬火9Cr2钢硬度的影响

Influence of overlapping amount on hardness of 9Cr2 steel by laser hardening

用3 kW连续CO2激光器对矫直圈用9Cr2钢,在功率2.2 kW和扫描速度800 mm/m in条件下进行搭接量分别为1、2、3、4 mm的激光表面淬火。用金相显微镜、扫描电子显微镜以及显微硬度计,分析9Cr2钢激光表面淬火后的硬化层分布和剖面硬度均匀性。结果表明,9Cr2钢激光淬火后硬化层分布形状为部分搭接的两月牙形,搭接处硬化层深度随着搭接量的增大而增加,在第二道激光扫描带对第一道激光扫描带热影响区出现硬度下降区域,且随着搭接量的增大硬度下降趋势减弱。

Laser surface hardening with respective overlapping amount of 1,2,3 and 4 mm on the regulator loop of 9Cr2 steel was carried out with 3 kW CO2 laser machine under the condition of 2.2 kW power and 800 mm/min scanning speed. The distribution of hardened layer and uniformity of sectioned hardness of 9Cr2 steel after the laser surface hardening were analyzed with metalloscope, and microhardness tester. The results show that the hardened layer distribution of 9Cr2 steel presents two crescent-shaped with lap. The depth of hardened layer on the overlapping region increases with the amount of overlapping increasing. There is an area of hardness descend in the heat influence area of the first laser scanning area caused by the second laser scanning area. And the trend of hardness descend becomes weaker as the increase of overlapping amount.